Separation of feldspar from quartz



Patented Oct. 6, 1942 SEPARATION OF FELDSPAR FROM QUARTZ Robert GibsonOMeara, Tuscaloosa, Ala., assignor to the Government of the UnitedStates of America, as represented by the Secretary of the Interior NoDrawing. Application April 5, 1940,

Serial No. 328,083

10 Claims. (Cl. 209-466) (Granted under the act of March 3, 1883 asamended April 30, 1928; 370 O. G. 757) The invention described herein,if patented, may be practiced and used by or for the United StatesGovernment for governmental purposes without the payment of any royaltythereon.

This invention relates to the preparation of ores for separation byfroth flotation and/or agglomerate table concentration film flotation orsimilar methods of concentration and particularly to the beneflciationof feldspar ores and their products. The invention is especiallyapplicable to the froth flotation and/or table concentration of feldsparfrom quartz and the separation of feldspar from other associatedminerals. It is a continuation in part of application Serial Number117,470.

In application of the present invention, great flexibility isachievable, as is particularly desirous in view of the wide variation inores encountered. Thus by this invention the various feldspars can befloated and/or tabled from the quartz in mixtures of variousproportions. In addition, the feldspar can be separated from some of theother commonly associated gangue minerals such as mice. and garnet bymodifying the procedure.

The'separation according to this invention is not based upon the sameproperties as any of the methods of beneflciation commonly used in thefeldspar industry. In continuance of experimentation on the flotation ofquartz from feldspar set-forth in a previous patent application, Ser.No. 117,470, it was discovered that changing from hydrochloric acid tohydrofluoric acid as a modifying agent reversed the order of flotation.

In this case the feldspar was floated from the quartz. A feed too coarsefor flotation, but prepared in the same manner as for flotation also wasseparated on a concentrating table. The feldspar agglomerated or filmedover the side of the table and the quartz was carried out by the rifilesto the end of the table. In this case the separation was not'based onthe specific gravity of the quartz and feldspar but upon the surfacepreparation. The feldspar was rendered waterrepellant as in flotation,and filmed whereas the quartz remained wetted by water.

In practicing the preparation of the ore according to this invention, itis desirable that the product be reasonably fine grained and that themineralogical constituents be liberated. The ground ore is mixed withwater forming a pulp or slurry tov which is added the necessaryreagents. The pulp is conditioned to insure mixing, and the separationis effected on any of the well known types of flotation machines and/rconcentrating tables.

The preparation of the feed for separation of the feldspar from thequartz by froth flotation or table concentration is effected in thisinvention by the use of cationic reagents of the type of trimethylcetyl-ammonium bromide or lauryl amine hydrochloride in conjunction withhydrofluoric acid, fluosilicic acid, other complex fluorine acids, theirsalts or their derivatives. In addition, a small'amount of hydrocarbonoils is beneficial in the treatment of the coarser mate rial. Some ofthe gangue minerals other than quartz are eliminated in this treatmentand others can be eliminated by first depressing the quartz and feldsparwith a mineral acid and later floating the feldspar in the normal mannerby the addition of fluorides and/or fluosilicates, fluoborates, or otherfluorine complexes of polyvalent elements like vanadium; zirconium ortitanium.

Whereas the original discovery of the unexpected reversal in selectivityin filming minerals took place with chemically pure hydrofluoric acid,it soon was found that impure hydrofluoric acid gave superior resultsand in attempting to find the cause, fluosilicic acid was tried as themost probable impurity. Other fluorine-metal complexes were then testedand specially good results were obtained with fluoborates andfluotitanates or the complexes formed by dissolving oxides of thesepolyvalent metals in excess hydrofluoric acid. Whereas chemically purehydrofluoric acid might give a grade of feldspar concentrate, theaddition of these further modifiers would raise the grade of theconcentrate to over 98%. The hydrofluoric acids of commerce are muchbetter adapted to the desired separation than are the pure hydyrofluoricacid preparations available.

For the purpose of illustrating this invention, two examples are heregiven. comprising applications which have been made of these inventionsto feldspar bearing products (1) in which the feldspars were preparedand separated from the quartz by froth flotation and (2) in which thefeldspars were prepared and separated from the quartz by tableconcentration.

The feldspar ore consisted of plagioclase fe df spar. albite andoligoclase. potash feldspar, microcline and orthoclase. quartz and minoramounts of mica. The ore was ground through 20 mesh for liberation ofthe constituents and sized on 48 mesh. The plus 48 mesh size wasprepared and separated on a concentrating table. and the minus 48-meshmaterial was prepared and separated by flotation.

The reagents used in treating the feed were as follows:

Pounds per ton of feed Reagents (2) on (1) On plus 48- minus 48- meshpart mesh part of feed of feed Lauryl amine hydrochloride "m... 0. 24 0.24 Hydrofiuoric acid 2. 3 2. 3 Fuel oil 5.4

These amounts of reagents gave satisfactory results but they couldundoubtedly be reduced and rebalanced without sacrificing results. Theor der of addition of the reagents appeared to have little effect on thesubsequent separation. The results of the tests follow:

(1) Flotation test on minus 48-mesh part of feed Distri- Assay ProductsWeight button A110 of Autos Percent Percent Rougher concentrate 58. 519.63 97, 9 Rougher tailing 41. 5 .59 2. 1

Composite (minus 48-rnesh part of feed) 100.0 11.73 100.0

(2) Table concentration test on plus 48-1ncsh pant of feed Distri- AssayProducts Weight bution of A120;

Percent Percent Table concentrate 44. 9 19. 18 94. 6 Table tailing 55. 189 5. 4

Composite (plus 8-1ncsh part of feed) l 100.0 9. 10 W0. 0

The resul s-of the combined flotation (1) and table concentration (2)test were:

ht A Eistri.

Combined )roducts "cig u 10H I of A110;

Percmi Percen! Table and flotation concentrate 49. 7 19. 37 96. 0

Table and flotation tailing 50. 3 .80 0

Composite (feed) 100.0 l0.03 \l00.0

The table and flotation products showed such a marked separation that noattempt was made t clean the concentrates nor to reduce the feldsparcontent of the tailings. However, this might be a desirable step in thepreparation of more In adcessfully used'in these separations might becalled cationic reagents, by which is meant organic reagents that ionizeto give small anions and large complicated cations. The latter probablytend to be adsorbed on acidic mineral surfaces thus filming them with agreasy substance that repels water and encourages attachment of airbubbles selectively. The selectivity in turn is dependent upon theaddition of hydrofluoric, fluosilicic, fluoboric acids or theirderivatives.

While I have described above certain preferred examples illustratingvarious applications of my invention, such examples and application arebest illustrative of my invention and are not to be construed asrestrictive either in this description or in the appended claims. Inface the separation is also adaptable to the separation of othersilicate minerals such as kyanite from quartz in which treatment withthe hydrofluoric acid the normal flotation or table concentration with acationic reagent like lauryl amine hydrochloride is reversed. Thus suchchanges may be made in the practices of my invention as are desirable toadapt my method to special applications, and the invention comprehendsall variations reasonably derived from my disclosures and embodying theprinciples thereof.

The foregoing may be briefly summarized as follows:

acidic mineral feldspar (1) Preparing feldspapquartz ores kyaniteconcentration froth flotation separation film flotation separationagglomerate separation (2) For suitable filming agents flotationreagents agglomeration agents cationic concentrating reagents (4) Beforeadding or in the presence of (5) And separating by steps under (2).

Accordingly, as used in the following claims, the term ores of the classdescribed is to be interpreted as including acidic minerals such asfeldspar, feldspar-quartz and kyanite; the term flotation is to beinterpreted as covering concentration by any of the usual methods suchas froth flotation separation, film separation, and agglomerateseparation; and the term hydrofluoric acid containing complexes ofpolyvalent elements to be construed as covering hydrofluoric acidcontaining such elements as fluosilicic acid, fluoboric acid andfluotitanic acid, or as contemplating hydrofluoric acid entirelycombined in the polyvalent form such as fluosilicic acid, or salt orderivatives of the above acidified with mineral acids; and the termconcentrating reagents" is to be construed as comprising suitablefilming agents, flotation reagents, agglomerate reagents or cationicconcentrating reagents.

I claim as my invention: Y

1. The process of separating aluminous silicate minerals of the groupconsisting of feldspars and kyanite from comminuted mixtures thereofwith quartz consisting in forming a slurry of the mixture with water, acationic flotation reagent yielding long chain cations containing fromtwelve to nineteen carbon atoms, and a modifying agent consisting ofhydrofluoric acid in which may have been dissolved multivalent,metaloxides from traces to almost complete neutralization of the acid,and separating the said aluminous silicate minerals by flotation.

2. In the separation of finely divided feldspar and quartz, the step offloating oil the fine feldspar by lauryl amine hydrochloride and an acidcontaining fluorine as part of its molecular structure, in an acidcircuit, substantially as described.

3. In the separation of finely divided feldspar and quartz, the step offloating off the fine feldspar by trimethyl cetyl ammonium bromide andan acid containing fluorine as a part of its molecular structure, in anacid circuit, substantially as described.

4. In the separation of finely divided feldspar and quartz, the step offloating off the fine feldspar by a cationic reagent, yielding longchain cations containing from twelve to nineteen carbon atoms, and anacid containing fluorine as a part of its molecular structure, in anacid circuit, substantially as described.

5. In the separation of finely divided kyanite and quartz, the step offloating off the fine kyanite by lauryl amine hydrochloride and an acidcontaining fluorine as a part of its molecular structure, in an acidcircuit.

6. In the separation of finely divided kyanlte and quartz, the step offloating off the fine kyanite by trimethyl cetyl ammonium bromide and anacid containing fluorine as a part of its molecular structure, in anacid circuit.

7. In the separation of finely divided kyanite and quartz, the step offloating oil the fine kyanite by a cationic reagent yielding long chaincations containing from twelve to nineteen carbon atoms and an acidcontaining fluorine as a part of its molecular structure, in an acidcircuit.

8. A process of separating quartz-containing ores of the groupconsisting of feldspar and kyanite ores which consists in forming anacid slurry of the comminuted ore with water, an acid containingfluorine as a part of its molecular structure, and a cationic flotationreagent yielding long chain cations containing from twelve to nineteencarbon atoms, and effecting flotation thereof.

9. In a process of separating feldspar ores by flotation, the step ofconditioning a wet pulp of the ore by incorporating therein an acidcontaining fluorine as a part of its molecular structure and a cationicfilming agent yielding long chain cations containing from twelve tonineteen carbon atoms.

10. A process of separating ores of the ,class described, which consistsin forming a wet pulp of the ore with at least oneof the acidicselectors from appended group A, and at least one of the agents fromappended group B, and thereafter effecting separation by at least oneappropriate operation of those of appended group C:

group A (acidic selectors) acids containing fluorine as a part of theirmolecular composition selected from the group consisting of hydrofluoricacid, impure hydrofluoric acid, fluosilicic acid, fluoboric acid,fluotitanic acid, and salts thereof in combination with mineral acid;

group B (agents) cationic reagents yielding long chain cationscontaining from twelv to nineteen carbon atoms;

group C (operations) froth flotation, agglomerate and film flotation.

ROBERT GIBSON OMEARA.

